/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.state.api.output.operators;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.fs.Path;
import org.apache.flink.metrics.MetricGroup;
import org.apache.flink.runtime.checkpoint.CheckpointOptions;
import org.apache.flink.runtime.jobgraph.OperatorID;
import org.apache.flink.runtime.state.CheckpointStreamFactory;
import org.apache.flink.state.api.output.SnapshotUtils;
import org.apache.flink.state.api.output.TaggedOperatorSubtaskState;
import org.apache.flink.state.api.runtime.NeverFireProcessingTimeService;
import org.apache.flink.streaming.api.graph.StreamConfig;
import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
import org.apache.flink.streaming.api.operators.BoundedOneInput;
import org.apache.flink.streaming.api.operators.ChainingStrategy;
import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
import org.apache.flink.streaming.api.operators.OperatorSnapshotFutures;
import org.apache.flink.streaming.api.operators.Output;
import org.apache.flink.streaming.api.operators.SetupableStreamOperator;
import org.apache.flink.streaming.api.operators.StreamTaskStateInitializer;
import org.apache.flink.streaming.api.watermark.Watermark;
import org.apache.flink.streaming.runtime.streamrecord.LatencyMarker;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
import org.apache.flink.streaming.runtime.tasks.StreamTask;
import org.apache.flink.util.OutputTag;

/**
 * Wraps an existing operator so it can be bootstrapped.
 */
@Internal
@SuppressWarnings({"unchecked", "deprecation", "rawtypes"})
public final class StateBootstrapWrapperOperator<IN, OUT, OP extends AbstractStreamOperator<OUT> & OneInputStreamOperator<IN, OUT>>
	implements OneInputStreamOperator<IN, TaggedOperatorSubtaskState>,
	SetupableStreamOperator<TaggedOperatorSubtaskState>,
	BoundedOneInput {

	private static final long serialVersionUID = 1L;

	private final long timestamp;

	private final Path savepointPath;

	private Output<StreamRecord<TaggedOperatorSubtaskState>> output;

	private final OP operator;

	public StateBootstrapWrapperOperator(
		long timestamp,
		Path savepointPath,
		OP operator) {

		this.timestamp = timestamp;
		this.savepointPath = savepointPath;
		this.operator = operator;
	}

	@Override
	public void setup(StreamTask<?, ?> containingTask, StreamConfig config, Output<StreamRecord<TaggedOperatorSubtaskState>> output) {
		((SetupableStreamOperator) operator).setup(containingTask, config, new VoidOutput<>());
		operator.setProcessingTimeService(new NeverFireProcessingTimeService());
		this.output = output;
	}

	@Override
	public void processElement(StreamRecord<IN> element) throws Exception {
		operator.processElement(element);
	}

	@Override
	public void processWatermark(Watermark mark) throws Exception {
		operator.processWatermark(mark);
	}

	@Override
	public void processLatencyMarker(LatencyMarker latencyMarker) throws Exception {
		operator.processLatencyMarker(latencyMarker);
	}

	@Override
	public void open() throws Exception {
		operator.open();
	}

	@Override
	public void close() throws Exception {
		operator.close();
	}

	@Override
	public void dispose() throws Exception {
		operator.dispose();
	}

	@Override
	public void prepareSnapshotPreBarrier(long checkpointId) throws Exception {
		operator.prepareSnapshotPreBarrier(checkpointId);
	}

	@Override
	public OperatorSnapshotFutures snapshotState(long checkpointId, long timestamp, CheckpointOptions checkpointOptions, CheckpointStreamFactory storageLocation) throws Exception {
		return operator.snapshotState(checkpointId, timestamp, checkpointOptions, storageLocation);
	}

	@Override
	public void initializeState(StreamTaskStateInitializer streamTaskStateManager) throws Exception {
		operator.initializeState(streamTaskStateManager);
	}

	@Override
	public void setKeyContextElement1(StreamRecord<?> record) throws Exception {
		operator.setKeyContextElement1(record);
	}

	@Override
	public void setKeyContextElement2(StreamRecord<?> record) throws Exception {
		operator.setKeyContextElement2(record);
	}

	@Override
	public ChainingStrategy getChainingStrategy() {
		return operator.getChainingStrategy();
	}

	@Override
	public void setChainingStrategy(ChainingStrategy strategy) {
		operator.setChainingStrategy(strategy);
	}

	@Override
	public MetricGroup getMetricGroup() {
		return operator.getMetricGroup();
	}

	@Override
	public OperatorID getOperatorID() {
		return operator.getOperatorID();
	}

	@Override
	public void notifyCheckpointComplete(long checkpointId) throws Exception {
		operator.notifyCheckpointComplete(checkpointId);
	}

	@Override
	public void setCurrentKey(Object key) {
		operator.setCurrentKey(key);
	}

	@Override
	public Object getCurrentKey() {
		return operator.getCurrentKey();
	}

	@Override
	public void endInput() throws Exception {
		TaggedOperatorSubtaskState state = SnapshotUtils.snapshot(
			this,
			operator.getContainingTask().getEnvironment().getTaskInfo().getIndexOfThisSubtask(),
			timestamp,
			operator.getContainingTask().getConfiguration().isExactlyOnceCheckpointMode(),
			operator.getContainingTask().getConfiguration().isUnalignedCheckpointsEnabled(),
			operator.getContainingTask().getCheckpointStorage(),
			savepointPath);

		output.collect(new StreamRecord<>(state));
	}

	private static class VoidOutput<T> implements Output<T> {

		@Override
		public void emitWatermark(Watermark mark) {
		}

		@Override
		public <X> void collect(OutputTag<X> outputTag, StreamRecord<X> record) {
		}

		@Override
		public void emitLatencyMarker(LatencyMarker latencyMarker) {
		}

		@Override
		public void collect(T record) {
		}

		@Override
		public void close() {
		}
	}
}
